1. Field of the Invention
The present invention relates to a sheet resin composition for back-grinding or underfilling of a silicon wafer, a process for manufacturing a semiconductor device, and a semiconductor device.
2. Discussion of the Related Art
With the recent increasing trends for high-density semiconductor devices, a package system employing integrated circuit (IC) comprising bumps, which is so-called xe2x80x9cflip chip,xe2x80x9d has been rapidly widely used. In addition, owing to the requirement of manufacturing a thinner semiconductor device, in order to make a semiconductor wafer thinner, the wafer is subjected to so-called xe2x80x9cback-grinding,xe2x80x9d wherein the back side of the wafer is ground. Particularly, in these several years, with the spread of a semiconductor device so-called xe2x80x9cchip scale package (CSP),xe2x80x9d a technique of making a wafer comprising bumps even thinner has been demanded in the market. When such a thin wafer comprising bumps is obtained, there has been employed a process comprising subjecting a wafer to back-grinding to a desired thickness, and thereafter attaching bumps. However, a thin wafer obtained after back-grinding is difficult to transport. Moreover, from the aspect of the recent progressing trend for enlarging a diameter of a wafer, there has been strongly demanded in the market the development of a technique for carrying out a back-grinding process after attaching bumps.
As a means for solving the above problems, there has been known a process in which an adhesive tape for back-grinding is adhered to the active surface (the opposite surface of the surface subjected to back-grinding) of a wafer on which bumps exist, and then the wafer is subjected to back-grinding. However, it is difficult to sufficiently fill the ruggedness of the wafer surface due to the bumps with the adhesive tape for back-grinding. Therefore, there arise problems that water penetrates to the active surface of the wafer during back-grinding, that the ruggedness caused by the bumps on the ground surface of the wafer remains after back-grinding, and the like. Therefore, wafers cannot be efficiently obtained, and the resulting wafer does not sufficiently meet the requirement of the market. Further, the adhesive tape for back-grinding must be completely removed from the wafer surface after back-grinding.
On the other hand, when a chip with bumps obtained by cutting the wafer subjected to back-grinding by means of dicing is attached on a substrate, a liquid thermosetting resin so-called xe2x80x9cunderfilling materialxe2x80x9d is filled between the chip and the substrate, and the thermosetting resin is cured (underfilling step). The underfilling step is an indispensable technique for securing the reliability for electric connection between the chips and the substrate. However, the number of its treatment steps is large, wherein the process comprises the steps of applying flux on a substrate; attaching a chip on the substrate; cleaning out the flux; filling an underfilling material between the chip and the substrate; and curing the underfilling material. Therefore, an even simpler process has been demanded in the market.
In accordance with the present invention, a sheet resin composition capable of excellently supporting a silicon wafer during back-grinding, and having an underfilling function during packaging a chip on a substrate is presented. Also in accordance with the present invention, a process for manufacturing a semiconductor device using the sheet resin composition, and the resulting semiconductor device, are presented.
More particularly, as a result of intensive studies in order to solve the problems associated with the prior art, the present inventors have found that by using a sheet resin composition having both of the function of supporting a wafer during back-grinding and the function of underfilling during packaging of a chip to a substrate, the back-grinding of the wafer is excellently performed, and the step during packaging of a chip to the substrate is simplified.
In sum, presented in accordance with various embodiments of the present invention are:
(1) a sheet resin composition comprising a resin composition capable of adhering to a silicon wafer, usable for supporting a silicon wafer during back-grinding and interfacial underfilling between a chip and a substrate;
(2) a process for manufacturing a semiconductor device, comprising adhering onto a silicon wafer a sheet resin composition to support the silicon wafer, subjecting the silicon wafer to back-grinding, and underfilling an interface between a chip and a substrate with the sheet resin composition as an underfilling material; and
(3) a semiconductor device obtained by the process as defined in item (2).
These and other features and advantages of the present invention will be more readily apparent from the detailed description set forth below taken in conjunction with the accompanying drawings.